Zetta Blog

Data Retention Best Practices and Policies

by Zetta Staff

Jul 7, 2014

It is not enough to just back up your data. For the best results, each data retention policy must be set just right.

On the one side, you could take a “keep everything forever” approach like the people on the A&E show Hoarders. That approach means you never lose any data, but it also means you are paying a lot for cluttered-up, useless storage space.

At the other extreme, you can keep too little data for too short a time. For example, the IRS, despite having an IT budget of $1.8 billion, was only keeping its email backup tapes for six months before recycling them. (Of course, the IRS requires citizens to retain documents for much longer than that.)

The fact is, there is no single backup retention policy that applies to all types of data. Just as a can of soup in your kitchen cabinet has a longer shelf life than the lettuce in your fridge, different data types need to be stored for different amounts of time.

But, assuming that one is in compliance from a business standpoint, how long should data be retained? Minimizing the length of time that data is being retained cuts the amount spent on storage. However, you don’t want to cut it too short and lose information critical to your business operations. While there are variations between businesses, the data being backed up generally falls into two categories – databases and files – with different data retention needs and policies.

See how our enterprise cloud backup solution works.

Data Retention Best Practices for Databases

Databases, such as SQL Server, Exchange and Oracle can have a high data change rate: up to 10% – 20% per day in extreme cases based on our experience in providing backup services to thousands of customers. This could mean that a week’s worth of retained daily changes would be roughly equal in size to a full data backup. Coupled with the fact that very old versions of databases are rarely needed in restore instances, we generally recommend one to two week retention on databases.

Data Retention Policies for File Server Data

File backups including Word documents, spreadsheets, PDFs and JPEGs have a much lower change rate – usually far less than 1% daily (files – especially office productivity documents – have a tendency to change a lot in their first 1-2 days of existence, and then remain static forever). This data generally needs to be stored for much longer periods of time, especially if required for compliance, so it would have a longer retention period.

These are the broad parameters, but they should be set for an organization’s particular needs.

Zetta’s management dashboard gives customers the ability to set up an unlimited number of backup and data retention policies. Within each policy, the backup administrator can set how many daily, weekly, monthly and yearly backups to maintain, in addition to the original backup.

Zetta Data Retention Setup

For further details on how to set up data retention policies, see our video on Retention Setup. The video explains how each backup retention policy affect the amount of online storage you use and how that affects your monthly costs. It then walks you through, step-by-step, how to configure such policies.